Rheumatic heart disease in children and adolescents, part 1: epidemiology, pathogenesis and diagnosis.

Rheumatic heart disease (RHD) remains a leading cause of acquired cardiovascular disease in children and adolescents globally, despite dramatic declines in high-income settings. This review synthesises contemporary evidence on the epidemiology, pathogenesis, natural history and diagnosis of rheumatic fever (RF) and RHD in young populations, with a focus on regions with high disease burden.Over recent decades, improvements in socio-economic conditions and access to healthcare have led to marked reductions in RF and RHD across much of Europe, North America and parts of Asia. In contrast, the disease persists at high prevalence in sub-Saharan Africa, South Asia, the Pacific Islands and among Indigenous and marginalised populations within high-income countries. In these settings, RF often occurs at younger ages, disease progression is accelerated and access to timely diagnosis and care is limited, resulting in substantial morbidity and premature mortality.Pathogenetic models continue to support immune-mediated valvular injury following Group A streptococcal infection, with increasing evidence that both pharyngeal and skin infections contribute to disease initiation. However, determinants of individual susceptibility and the mechanisms underlying progression from infection to chronic valvular damage remain incompletely understood. Importantly, recent observational and trial data challenge the traditional linear paradigm in which clinically apparent RF precedes RHD, demonstrating that many children develop early valvular disease without recognised RF episodes.Echocardiography has transformed the diagnosis of RHD, revealing a substantial burden of clinically silent disease and enabling earlier identification along the disease spectrum. Updated World Heart Federation echocardiographic criteria and recent WHO guidelines now support screening in high-risk populations and a staged approach to disease classification. Evidence that secondary antibiotic prophylaxis can prevent progression of early RHD reinforces the importance of early detection.Together, these advances reframe RHD as a preventable chronic disease with a detectable early phase, providing a strong foundation for effective prevention, timely diagnosis and improved outcomes in children and adolescents living in endemic regions.